Only expose pthread_setaffinity_np call when HAVE_SETAFFINITY is defined

Fixes #848 (closed)

added bug label

assigned to @matthieu

I think threadpool_set_affinity_mask() will fail if SETAFFINITY is not defined.

That function is not called unless HAVE_SETAFFINITY is defined, so use of it is already banned. Without HAVE_SETAFFINITY it would be a noop anyway as would pinning, so the fix isn't relevant.

Tested by the person reporting the issue. All works.

Thanks!

merged

mentioned in commit 2c56c013